New compositions or vaccines with an improved immunogenicity are always needed. As one strategy, adjuvants have been used to try and improve the immune response raised to any given antigen and/or reduce reactogenicity/toxicity in the host.
Oil in water emulsions per se are well known in the art, and have been suggested to be useful as adjuvant compositions (EP 399843; WO 95/17210).
WO95/17210 discloses oil in water emulsions comprising from 2 to 10% squalene, from 2 to 10% alpha tocopherol and from 0.3 to 3% tween 80 and their use alone or in combination with QS21 and/or 3D-MPL.
WO99/12565 discloses oil in water emulsion compositions comprising a metabolisable oil, a saponin and a sterol. The oil in water emulsions further comprise 3D-MPL.
WO99/11241 discloses oil in water emulsions comprising metabolisable oil and a saponin, wherein the oil and saponin are present in a ratio of between 1:1 and 200:1.
There is still a need for improved vaccine and immunogenic compositions that provide a suitable immune response and are less reactogenic in the host.